[Nepomuk] Review Request 108550: Cancel in-flight dbus queries to avoid leaks.

[Xuetian Weng]

> On Jan. 22, 2013, 5:46 p.m., Xuetian Weng wrote:
> > nepomuk/query/queryserviceclient.cpp, line 412
> > <http://git.reviewboard.kde.org/r/108550/diff/1/?file=108692#file108692line412>
> >
> >     reply.value() actually will block until reply is returned.
> >     
> >     see QDBusPendingReply document.
> >     
> >     Is that what we really want here (I'm not familiar with nepomuk, so if this pending call always return immediately, that would be more acceptable here.
> >     
> >     And you should check reply.isError() first.
> >     
> >     I think the correct approach is also doing garbage collection on server side.
> >     
> >     query services can get the dbus sender name (by subclass QDBusContext), and mark the query with service name (the private name like :2.3), once all name associate to the same query disappeared, this query can be garbage collected.
> >     
> >     This can also avoid the possible crash on client side and leave a dangling query.

Ah.. so garbage collection is already done.. I just saw the related code, ignore my latter part. So what this patch really affects is some "long" running client..


- Xuetian


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On Jan. 22, 2013, 2:55 p.m., Till Adam wrote:
> 
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> http://git.reviewboard.kde.org/r/108550/
> -----------------------------------------------------------
> 
> (Updated Jan. 22, 2013, 2:55 p.m.)
> 
> 
> Review request for Nepomuk, David Faure and Vishesh Handa.
> 
> 
> Description
> -------
> 
> Cancel in-flight dbus queries to avoid leaks.
> 
> If close() is called on the query service client while dbus queries
> are still in flight, they were left dangling. This change makes sure they are
> properly cancelled. Without this, all such dangling queries are maintained by
> nepomuk and updated constantly, causing extreme loads, over time.
> 
> 
> Diffs
> -----
> 
>   nepomuk/query/queryserviceclient.cpp 7d3ef0fdff56ae91b89ab95d140634af06b4c218 
> 
> Diff: http://git.reviewboard.kde.org/r/108550/diff/
> 
> 
> Testing
> -------
> 
> I've been running this for several hours with no more hanging queries. Used to accumulate 10 or more in the same time frame before.
> 
> 
> Thanks,
> 
> Till Adam
> 
>

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